Conventional mobile terminals have to suspend the execution of an application(s) during an update of an operating system (hereinafter, “OS”). As a result, a user cannot utilize the operation (hereinafter, “function”) of the application(s) during the update. Thus, the OS is updated at hours such as midnight during which the frequency of use by the user decreases. However, different from general-purpose computers, the embedded system of the mobile terminal is supposed to operate 24 hours a day, 365 days a year. Thus, the suspension of the execution has been a problem.
For servers, two methods for updating the OS without any suspension have been suggested. One of the methods (hereinafter, “conventional technology 1”) has a stand-by system other than the main system and causes the stand-by system to operate during the update of the main system (see, for example, Japanese Laid-Open Patent Publication Nos. S54-106146 and 2003-330744). The other one of the methods controls a virtual machine to execute software including the OS during the update (hereinafter, “conventional technology 2”).
However, the conventional technologies 1 and 2 have a problem of an increased scale and/or cost of the embedded system. On the other hand, without the substituting stand-by system or the virtual machine, the execution has to be suspended.
As described above, the embedded system of the mobile terminal is supposed to operate 24 hours a day, 365 days a year. However, there has been a problem in that the user cannot utilize the function during the update and the execution has to be suspended.